The inventor herein has engineered and implemented lightning prevention systems for over twenty years. U.S. Pat. No. 4,180,698 (1979) to Carpenter, Jr. teaches an ionizer structure rising above the earth's surface and providing a uniform field shape in combination with an endless ground collector structure having service wires to the ionizer structure. The ionizer structure in its preferred mode has a plurality of dissipater elements having a geometry calculable so as to form the lines of equal potential.
U.S. Pat. No. 5,043,527 (1991) to Carpenter, Jr. discloses a lightning Dissipation Array System(DAS) having an optimal array of ionization points on a grounded invented hemisphere array.
U.S. Pat. No. 5,073,678 (1991) to Carpenter, Jr. discloses a Spline Ball Terminal (SBT) which can act to dissipate a lightning charge or in failure mode to collect a lightning strike from all directions, even sideways. The SBT is an SBI having a base rod.
Refer to prior art FIGS. 1, 2. The thunderheads are electrically charged bodies suspended in an atmosphere that may be considered, at best, a poor conductor. During a storm situation the charge will continue to build up within the cloud until the field strength reaches a point where the insulation quality of the air gap is no longer effective and breakdown takes place. The specific breakdown point varies with atmospheric conditions. It is generally taken as 3 kilovolt per centimeter for negatively charged storm cells and 5 kilovolt per centimeter for positively charged cells. The charging action or charge separation within the storm cell usually leaves the base of the cloud with a strong negative charge. In about ten percent of the cases the opposite seems true. This resulting charge induces a similar charge of opposite potential into the earth as illustrated by FIG. 1. The charge center 20 is concentrated on the earth's surface 22 just under the cloud 24 and of the same size and shape as the cloud 24. As structures 26 intervene between the earth and cells they are likewise charged shorting out a portion of the separating air space 28. The ultimate result can be either a triggered strike because of the reduced air space or because it was high enough to start an upwardly moving leader.
The foremost objective of the invention is to reduce the electrostatic potential between the area or facility of concern and the passing cloud's cells to a level where the ongoing atmospherics induce no deleterious effects into the facilities of concern. Some of these effects include, but are not limited to: direct lightning strikes or transients induced thereinto, communications circuits, meteorology sensors, process control equipment, status sensors, power transmission and distribution lines, telephone circuits, switch gear substations, FM and AM radio stations, television, cable television, microwave and other sensitive power and electronic equipment. This invention also eliminates the bound charge phenomena associated with, for example, petrochemical storage and processing facilities.
The lightning strikes, or flashes, are created when a cloud potential exceeds the breakdown potential of the surrounding air. As a result, a step leader is formed and moves rapidly earthward meeting an upward moving leader a short way above the earth. The deleterious transients are created by either the rapid change in the electrostatic field created by these discharges or by the rapid movement of the earth charge from the point where it was induced into the earth to the point where the lightning strike was terminated. This invention eliminates or minimizes, and in many cases eliminates the root cause of these phenomena by significantly reducing and suppressing, respectively, the electrostatic field and the conducting the charge away from the area of concern.
The ionizer 50 forms an inverted hemisphere. The lines of force 52 form a bell curve.
There are situations where a tower having a hemispherical dome as shown in FIG. 2 is not practical. The reasons may include:
a) wind load; PA1 b) interference with an antenna; PA1 c) physical clearances; and PA1 d) need for a concentration of ionization points in a small area.
The present invention provides an equivalent lightning prevention system without the need to erect an inverted hemispherical dome. The structure taught herein uses clusters of high-density ionizing balls known as Spline Ball Ionizers (SBI's) or similar devices. The SBI's are arranged geometrically into trees having a wide base and a narrow top. The resulting lines of equal potential formed around the new structure form approximately the same desired bell curve as shown in FIG. 2. FIG. 3 shows a Spline Ball 33. It is relatively low cost to manufacture and install. The SBI 33 comprises a stem and a ball 91. The ball 91 is composed of multiple branches 92. Branches 92 may fold downward around stem 90 for ease of packaging and installation. Ball 91 and stem 90 are electrically conductive, preferably made of copper. The diameter w of ball 91 ranges from 24 to over 60 inches varying with the width of the tower it protects.